Feature

Solar mapping: demystifying solar potential

01 July 2009Dianna Herbst

Talk to anyone and they'll tell you in principle they think solar energy is a good idea. But we haven't harnessed it for conversion to electricity utnil fairly recently and even today barriers still exist that -prevent solar energy entering the mainstream. But could solar mapping help bring the technology further into the public domain?

PV production has been doubling every two years, increasing by an average of 48% each year since 2002, making it the world's fastest-growing energy technology. However, some perceived barriers for its widespread use include the expense of installation, the quantified return on investment, and the availability of experienced resources for installing and maintaining equipment.

Governments around the world are now working at removing these barriers and creating a path to more widespread adoption. Part of this means providing funds to cities and counties for the implementation of clean energy sources.

Many cities and local Governments are seeking ways to provide greater access to solar energy, ease permitting and licensing challenges and make solar energy more accessible and affordable for homeowners and businesses. And perhaps one of the most dynamic means of removing the barriers to solar adoption has been the advent of the solar map.

Solar mapping portals – gateway to adoption?

In its simplest form, a solar map uses Google Maps or Microsoft Virtual Earth to identify the solar installations within a given area such as a city or a county. Applied to an online solar portal – an access point for citizens and business owners to access detailed and area-specific solar information – the map provides a visual snapshot of the solar progress of the area.

But a solar portal can do more than just show solar installations already in place. A solar portal can also address many factors that play into the decision-making process when a solar energy system is to be installed. These would include:

Solar electricity potential (based on geography and building characteristics);

Installation costs;

Availability of rebates;

Estimated energy savings;

Listings of installation contractors and who to contact to get started.

And solar mapping has now been to taken to a new level with some solutions now able to look at every structure on a map to calculate the estimated potential environmental benefits and monetary savings that would result from installing solar energy panels on the building.

One example of such technology is Solar Automated Feature Extraction (S.A.F.E.), a proprietary software solution used by USA, Denver-based CH2M HILL. S.A.F.E assesses the precise solar potential of each building in a city or neighbourhood, rooftop by rooftop, through a combination of aerial imagery and advanced 3-D modelling. This includes accurately measuring elements of a rooftop structure (including air conditioning units and ducting); the azimuth or direction of the sun; shadows cast by other structures; and the slant of the roof.

With such detailed analysis, residents and building owners can perform return-on-investment calculations that would otherwise take numerous on-site visits and weeks to complete.

Case study – Solar mapping in action in the USA

US municipalities are getting support from the Federal Government in their efforts to harness the sun as a source of electric power. The Solar America Cities program for example is a partnership between the US Department of Energy (DOE) and a select group of cities across the country that have committed to accelerating the adoption of solar energy technologies and systems at the local level.

Solar systems work to help building occupants save money by combining PV and traditional electricity. When the solar system generates more electricity than needed, the electricity meter will run backward. If an owner needs more electricity than the PV system generates, the owner uses the electricity from the utility as usual. Called “net-metering,” the combination reduces an electricity bill to the difference between how much a solar system produces and how much electricity is used.

The selected Solar America Cities have teamed up with municipal, county, and state agencies, nonprofit organisations, universities, utilities, developers, and solar companies to accelerate the adoption of solar energy. Several of the cities have completed, or are in the process of creating, solar mapping portals.

Such solar map portals with their property-specific solar estimates, give residents and businesses the potential to learn about the benefits of solar for a precise location.

“The Solar America Cities were deemed such because they've taken a leadership role in the nation's adoption of solar energy,” said David Herrmann, a project manager from CH2M HILL, a Colorado-based firm involved in solar mapping. “The solar mapping portal has been a highly visible component of many city programs, allowing a window into the city's solar potential and helping speed the adoption of solar – rooftop by rooftop.”

San Francisco was the first city to determine the solar potential of every building in a city using S.A.F.E. analysis. Integrating the map as the cornerstone of a solar portal, it provides the city and county of San Francisco's Department of the Environment a one-stop site to engage citizens on solar outreach efforts.

As part of the project, the Web portal enables residents and building owners to easily view their rooftops, calculate the available square footage for panels, mock up solar panel placement, estimate how much money they will save, and choose from a listing of available installers. Residents can also see whether any of their neighbours have adopted solar energy, which buildings in town have solar applications, as well as get detailed information on tax rebates.

Since the portal has been implemented and made available to the public, PV installations have grown by 60% and the amount of solar electricity generated has doubled. “Making the costs readily apparent has taken some of the guesswork and mystery out of solar decisions and helped ease the citizenry's approach to implementation,” says CH2M HILL's Herrmann.

And according to Johanna Partin, renewable energy program manager for the San Francisco Department of the Environment, “the solar mapping solution will help the city and county of San Francisco reach its goal of 10,000 solar roofs by 2012”.

Other cities in the USA currently investing solar mapping include Los Angeles County, Portland, Sacramento and San Diego.

In a city known more for its rain than its sunshine, Portland, Oregon, is aggressively pursuing solar power as an alternative energy source. Portland built its Oregon Clean Energy Map as a tool to help meet its 2012 goal of five MW of solar-generated electricity.

The Oregon Clean Energy Map is unique because it not only details existing systems and estimates potential for PV installations, it also captures thermal solar installations and energy potential. Thermal solar systems are specifically designed to collect, absorb, and distribute heat and are much less expensive and efficient. Solar thermal power is generally used to heat water for domestic use and heat the interior of buildings.

“Thermal systems are one of the most affordable ways to go solar and can offset one of the biggest energy uses in a home – the water heater. Residential solar water heating systems typically save 60% of the energy used to heat water in an average Oregon home,” said Herrmann.

The Oregon Clean Energy Map provides detail about every existing photovoltaic and water-heating solar installation in the city of Portland and Multnomah County. As residents scroll over existing installation sites on the map, details about the size and type of system, photos of the systems as supplied by some property owners, and links to the installer's contact information are provided.

Additionally, with information from the City's parcel database, the map provides an estimate of each building's solar potential based on the size of the roof, the amount of unshaded area and current rebate program information.

Solar initiatives internationally

There's certainly no lack of international attention focused on reducing carbon emissions through solar. As more and more of the world takes aggressive steps toward implementing alternative energy sources as primary electricity generation to mitigate the economic impact of skyrocketing oil prices and the environmental impact of pollution, solar maps could become an important tool for regions converting to the alternative and abundant energy source.

One such ambitious undertaking is, ironically, in the oil-producing nation of Abu Dhabi where the Masdar Initiative is underway. Masdar, which means “the source” in Arabic, is building Masdar City, a carbon neutral, zero-waste city, powered entirely by renewable energy. The initiative is leveraging established renewable energy industries such as solar, but also investing in its own future-energy innovations.

There is also an international movement similar to the DOE's Solar America Cities program that has been in place since 2004. The objective of the International Solar Cities Initiative is to support United Nations energy and climate policies by stimulating the interest of cities into becoming benchmark cities that commit to ambitious emission reduction goals. The initiative helps cities integrate renewable and energy efficient technologies and industries into environmental, economic and city planning, and provides scientific support for the validation and design of effective measures and policies for its solar cities.

“Though the burden of cost and responsibility for implementation may be allocated differently, a solar mapping portal provides the same benefit for a home in Abu Dhabi as it does in Alabama or anywhere around the world – and the faster we, as an international community, can break down those barriers the more efficient our alternative-energy economies will become around the globe,” concludes Herrmann.

About the author

Dianna Herbst is an employee of CH2M HILL in the company's Enterprise Management Solutions.

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